Importance of Sleep
It has been proposed, by some, that humans do not really need to
sleep, and that we do so only out of habit. However, much research
would suggest otherwise. It is true that some individuals (e.g. those
suffering from insomnia) are able to live on very small amounts of
sleep, but nevertheless, they do need some.
Studies of sleep deprivation have found that there may be severe
consequences of not sleeping at. Randy Gardner, for example, went
without sleep for 11 nights. By the end of this period, he suffered
severe hallucinations and paranoia. He found interacting with other
people difficult and even lost some of his sense of personal identity.
There were, however, no long term consequences. There is evidence that
lack of sleep may even lead to death. One 52 year old man's
hypothalamus, including the part which regulates sleep, was severely
damaged due to a viral infection. He was unable to sleep at all and
died within a relatively short period of time. Although it is possible
that the damage to the hypothalamus rather than the lack of sleep was
the actual cause of death, research using rats has found that healthy
rats, which are deprived of sleep, may die within approximately 30
All this is evidence that sleep serves important physiological
functions. Oswald (1980) proposed that sleep is the time in which most
tissue growth and repair occurs and that it is therefore necessary.
Others have argued that this growth and repair can take place during
periods of micro-sleep, however, and that extended periods of sleep
are not necessary. It is worth noting, though, that babies spend a
much larger proportion of the day in sleep compared to adults and so
perhaps this allows the rapid growth (especially of brain tissue)
which occurs in the first months of life to take place.
Stern and Morgane put forward an alternative restoration theory,
proposing that during sleep, the levels of neurotransmitters in the
brain are restored. Again, this theory would seem plausible, in part
because people who take antidepressants (these drugs help restore
neurotransmitter levels) appear to need less REM sleep than normal.
Evolutionary theories would perhaps seem less likely than restoration
ones in terms of explaining the apparent need for sleep. According to
hibernation theory (Webb, 1982), sleep has evolved to enable energy to
be saved at times when being awake and active would be of little use
to animals (e.g. because it is too dark for them to do anything).
However, this does not seem to be applicable to humans - in order to
meet the current demands of society (such as work and social
activity), being awake all of the time would be of extreme value,
especially as electric lights and so on mean that 24 hour activity
would be possible. It is difficult to see, then, how...